Bearings of the pre-cited type for cylinders or drums of printing machines are often also configured also as eccentric bearings. One such bearing configured as a triple ring rolling bearing is disclosed in DE 41 26 545 A1. This triple ring bearing comprises an inner bearing having an inner ring that is connected to a journal of a rubber blanket cylinder and comprises an outer raceway that is concentric with the journal. The triple ring bearing further comprises an outer bearing having an outer bearing ring that is arranged in a bearing housing and comprises an inner raceway that is concentric with the bore of the bearing housing. A one-piece, eccentric intermediate ring is arranged between the inner bearing ring and the outer bearing ring and comprises raceways for the inner and outer bearings, and said intermediate ring can be pivoted in peripheral direction by actuators situated outside the bearing housing.
Between the inner bearing ring connected to the journal and the eccentric intermediate ring, and between the outer bearing ring and the eccentric intermediate ring, are arranged for giving radial support, rows of radial bearings in the form of cylindrical roller bearing rows, and at least on one axial end next to a cylindrical roller bearing row are arranged thrust bearing rows, e.g. ball bearing rows or cross roller thrust bearings in the inner bearing or ball bearing rows in the outer bearing for providing a separate support of thrust forces.
Such eccentric bearings are always used in the printing industry when several printing cylinders are arranged next to each other with their outer peripheral surfaces in contact with each other. Due to the adjustable eccentricity of the individual bearings, the cylinders can be placed against each other or separated, the aim being to obtain as straight a connecting line as possible between the cylinders. The displacement of the individual cylinders in a direction perpendicular to the axis of rotation is required when the printing operation is started or stopped.
A drawback of such eccentric bearings is that they have a large radial design space requirement especially if the movement of displacement is large. The problem is aggravated if small-diameter cylinders are used. In the extreme case, it is possible that the principle of eccentricity can no longer be utilized for the displacement of the cylinders because the bearings would then have to be larger than the cylinders to be displaced.
A further drawback is that eccentric bearings can execute a displacing movement only along a curved path. The displacing movement is rendered more difficult if several cylinders are arranged next to one another. Efforts have been made to resolve this problem through an eccentric mounting of the two journals of each cylinder. It is obvious that such a multiple eccentric mounting of individual components of a complete bearing arrangement is complicated and work-intensive and therefore expensive.